Attachment



H. A. wELToH AND H. 1. HYT. ATTACHMENT FoH PLASTIOMIXING Mugs.

APPLICATION FILED FEB.4. \9l5.

Patented July 1, 1919.

3 SHEETS-SHEET l- O O MIN o Al lllllll H. A. WELTON AND H. J. HOYT.

ATTACHMENT FQR PLASTIC MIXING MILLS. APPLICATION FILED FEB. 4. 1915.

1,308,132. Patented Julyl, 1919.

SSHEETS-SHEET 2.

II. A. wIiLIoN AND II. I.-I`I0YT.

TTACHMENT FOR PLASTIC MIXING MILLS.

APPLICATION FILED FEB. 4. I9I5.

Patented July 1, 1919 3 SHEETS-"SHEET 3.

uIllllllllllll STATES PATENT OFFICE.

A. WELTQN AN'D HOMER J. HOY-T, 0F DETROIT, MICHIGAN, ASSIG-NOItS T0 MORGAN & WRIGHT, A CORPORATION F MICHIGAN.

ATTACHMENT FOB- PLASTIC-MIXING MILLS.

To all 'whom 'it may concern:

provements in Attachments for Plastic-Mixing Mills,vof which the following is a full,

clear,` and exact description.

This invention relates to mills for mixing plastics, more particularly rubber, and has for an object to provide an improved appa` ratus embodying the combination of a r1g1d support, frame, or pan, and an apron which is capable of being easily` installed on any Y mill and will operate most effectively under all conditions of service without getting out of order. f

Hitherto, it has been customary' to equip mills for milling plastics such as rubber and `vthe like with an endless apron which carries the compounding and filler materials as well as portions of the rubber which gravitate between the milling rolls back into the batch upon the 'upper sides of the rolls. Hitherto the bearings for the rollers of this apron' have been vmounted onthe housings of the mill and 'this was not a mechanical success, because pro r` alinement of the rollers could not be Aobtainecil and' the apron would ride improperly. 'To obviate these disadvantages the present invention employs a rigid snpport, frame, or pa'n upon which the'apron rollers are carried and held properly alined, whereby the association of the apron with such :rigid support,- frame, or pan can be installed upon any mill with. assurance that the apron will atall timesride properly and effectively perform its function under the severest conditions of service.

A further object of the invention is to promote the long life and eiliciency of the apparatus by the provision of a counterbalancing Weight, cable, and windlass device so connected with the delivery end of the apron in Vcombination with pivoted guide rods for the apron, that the apron 4may readily yield transversely as well as longitudinally of itself in conforming to mequalities in the sheet of plastic material accumulated upon one of the mill rolls. p

A further object of the invention is the rovision of shelves, lpreferably in the form of leather strips, w` ich proJect over the Specification of Letters Patent.

Application filed February 4, 1915. Serial No. 6,015.

Patented July 1, 1919.

edges of the apron and prevent any of the compound orv other material which may work over the ends of the milling rolls from dropping down inside the apron and mutilating theapron vas it passes over its rollers, the gravitating material-accumulating upon the shelves from which it is brushed by the operator on to the apron and thereby carried back into the batch.

The invention .will be readily understood by reference to the accompanying drawings in which;

Figure 1 is a plan view of a mill equipped with the' invention; f v

Fig. 2 is al longitudinal sectional view on the line'Qf-2, Fig. 1; u 4

Fig. 3 is a rear elevation of the mill with the apron and milling rolls removed Fig. 'l is a detail view showing the counter-weight and its windlass.

Referring now to the drawing in which like characters of reference designate similar parts, a mill for mixing plastics, more particularly rubber, is shown comprisin a frame 10 between the housings 11 of which are mounted milling rolls 12 and 13 that are rotated toward each other by suitable driving meansv (not shown). l

In carrying out theinvention We provide a rigid support, frame, or pan 14 which is adapted to be removably supported undernea-th the milling rolls of any mill, as shown at 15 for instance, .andwe preferably form this of cast iron to assure the utmost rigid; ness. While this part is shown in the drawing as a pan, it is to be' understood that a rigid support or frame of any description may be employed so long as it provides rigidly connected points at which bearings for the apron rollers, hereinafter described, may be located, it being of course understood that in the event of a rigid skeleton frame or support being used a pan of some description should lalso be used in connectionso as to catch any material gravitating from the bottom side of the apron and prevent the waste or adulteration of such material by its falling upon the floor underneath the mixing rollers.

Therigid support, frame, or pan is of such length that it projects forwardly and also rearwardly beyond the milling rolls as illustrated so as, to be easy of access for removal of'its contents.

Associated with the above described rigid support, frame, or pan is an endless apron 16 that is trained over rollers 17, 18 and 19, the upper side of the apron having a por- 5 tion passing' underneath the milling rolls to receive the gravitating material therefrom and having a delivery portion held up against the front side of the roll 12, whereby the latter drives theA apron by friction direct or indirectly through the instrumentality of the plastic material which adheres in sheet form to the roll 12.

The bearings 20 of the rear roller 17 are adjustably mounted on the rigid support, frame, or pan 14 through the instrumentality of a pin and slot connection 21, 22, and may be moved longitudinally of the machine through the instrumentality of adjusting bolts 23, the roller being loosely or pivotally journaled in these bearings, whereby each adjusting bolt may be operated independently of the other to effect proper alinement of the apron and assure its most effective operation upon any particular mill to which the apparatus may be applied.

The bearings 20 of the lower front roller 18 are preferably rigidly secured to the support, frame, or pan by bolts 21', and are of such height that the upper side of this roller projects above the rear roller 17, so

that the endless apron will slope rearwardly and avoid contact with the rear milling roll 13 of the mill upon which the apparatus is installed.

The upper front roller 19 is journaled in bearings 24 which are slidably fitted on Ainclined guide rods 25 which are pivoted at their lower ends to brackets 26 carried by the rigid support, frame, or pan 14, as shown at 26. These guide rods may thus swing outwardly independently of each other, and to permit of this the roller 19 is loosely or pivotally journaled in the bearings '24. As will `be hereinafter more fully explained the roller 19 is yieldably held at its upper limit of movement on the guide rods by a counter-weight 28, so that the delivery end of the apron is held against, driven by, and coacts with the mill roll 12 in returning gravitating material into the batch.

The counter-weight 28 is operatively connected to the roller 19 through the instrumentality of cables 29 connected at their forward ends to the bearings 24 and at their rear ends to respective grooved pulleys 30 fixed to a shaft 31 which is journaled in bearings 32 adapted to be secured to the mill housings above the rear roller 17 of $0 the endless apron. The counter-weight is secured by a cable 33 to a grooved pulley 34 fixed to said shaft 31, and by its weight turns said shaft with consequent winding of the cables 29 on their pulleys 30, whereby the roller 19 is yieldably pulled upwardly.

By virtue of the guide rods 25 being rockable independently of each other, when inequalities of thickness of the sheet of plastic material on the roll 12 occur, the corresponding portion of the apron may yield and follow such inequalities, that is the apron can yield transversely of itself. Obviously when this yielding occurs, the counter-weight will be raised by movement of either one of the cables 29, with consequent slackening of the other of these cables, thus relieving that particular portion of the belt and its mountings which are not being urged outwardly by excess accumulation of material, from stress. For limiting inward movement of the roller 19 in the direction of the roll 12, stops 27 are fixed to the housings of the mill above the roll 12, against which stops the upper ends of the guide rods 25 impingc.

For releasing the counter-weight a cable 35 is connected to a grooved pulley 36 fixed to the shaft 31 and is Wound upon a grooved pulley 37 carried on a stub shaft 38, through the instrumentality of a ratchet and pawl control lever designated in 'general by the 90 numeral 39. Upon the lever being rocked to wind the cable 35 on the pulley 37, the shaft 31 will be rotated and the counterweight lifted by winding of its cable upon its pulley 34, whereby the cables 29 and 95 are slackened allowing the roller 19 to gravitate upon the rods 25. In this released position of the parts the delivery end of the apron exposes the front of the roll 12, whereby the sheet of plastic material may be cut 10g from the roll.

accumulates on these shelves and thus is prevented from entry inside the apron and mutilating the apron as it passes over its rollers. The accumulated material is from time to time brushed by the operator from these shelves on to the apron and is thereby carried back into the batch.

In operation, a batch of material is inserted between the upper sides of the rolls 12 and 13 and the machine started. At first 120 the material will in part pass down between the rolls and gravitate on to the traveling apron which conveys it back over the front side of the roll 12 into the batch. This operation is continued until eventually the material having reached a plastic homogenous condition, adheres to the roll 12 in sheet form in which condition it is ready for removal. The machine is then stopped and the lever 39 operated to release the counter- 130 weight whereupon the roller 19 gravitates and exposes the roller 12 for removal of the material therefrom.

It is understood that'various modifications may be resorted to, and when in the claims we use the term controlling means Weintend to include any' desired control for the apron, it being simply essential to the prac tice of the invention that the apron be associated with an integral support, whereby the equipment as a unit may be installed upon any -mill Without alterations to the mill.

Having described our invention, what we claim and desire to have protected by Letters Patent is:' l l,

1. .In apparatus of the kind described, in combination, mixing rolls, an apron contacting with material passing through said rolls, members for supporting said apron comprising a contact member holding said apron in contact with part of the surface of said rolls, a support for s aid contact member, and weight operated means for yieldingly resisting movement of said contact member toward its support when material of increased thickness is passing the apron and for automatically returning said member when the material has passed.

2. In apparatus of the kind described, in combination, mixing rolls, anapron, rollers supportin said apron including a contact roller holigling said -apron in contact with material passin over one of said rolls, a support for sai contact roller, and weight operated means for yieldingly resistlng movement of said contact roller toward its support when material of increased thickness is passing the apron and for automati cally returning said roller when the material has passed. i

3. In apparatus of the kind described, in combination, mixing rolls, an apron, rollers for supporting said apron including'v a contact roller `sl1dably mounted on pivotally held upri ht guides adjacent one of said mixing ro s, said contact roller holding said apron in contact with material passing over one of said mixing rolls, and Welght operfated means for yleldingly resistin move-y ment of said contact roller downwar ly upon said upright' guides when material of increased thickness is passing the apron and for automatically returning said roller whe the material lhas passed. A

4. In apparatus of the kind described, in combination, mixing rolls, an apron, supporting rollers for said apron including a pair ofrollerslbelow the m1x1ng rolls and a contact roller above said pair of rollers,

said contact roller causing said apron to contact with material passing over one of said mixing rolls, pivotally supported sub` stantially upright rods for supporting said 'Contact roller, bearings for said contact roller slidably mounted on ysaid upright operatively connected to and exertin vrods, weight operated means for yieldingly holding" said bearings in raised positions upon said rods, manually operated me'ans for releasing sald first named means to per- .mit said bearings to descend, and means for positively connecting the said two holding and releasing means. l

5. An attachment for mixing mills .embodying a support adapted to be secured to a mill underneath the milling rolls thereof, spaced rollers carried by the support, inclined guide rods pivoted at their lower ends to said support, a roller mounted to slide on said uide rods, an apron trained over all of said rollers, a tension device yieldably holding the* last named roller at its upper limit of movement upon said guide rods and permittin independent rocking of either of said gui e rods,and stops limiting movement of said guide rods toward said milling rolls.

6. An attachment for mixing mills embodying a support adapted lto be secured to a mill underneath the milling rolls thereof, an apron carried b said support,

a yieldably mounted roller olding the decombination, mixing rolls, an apron contacting with material passing over one of said rolls, rollers for su porting said apron including a contact rol er slidably mount ed on a pair of upright guides pivotally los supported adjacent the lower portion of one of said mixin rolls, a single rotatable shaft for contro ling the motion of said contact roller, a weight forl rotating said shaft and cable members attached respectively to the ends of said contact roller and to said rotatable shaft, whereby material passing between said apron and the adjacent mixing roll will cause one or the other of said upright guides to -move outwardly or inwardly under the control of sald 'weight and 'when one of said guides is moved the other will be free to move. v

8. In apparatus of the kind described, in combination, mixing rolls, an apron contacting with material passing over one of said rolls, rollers forv supporting said apron including a contact roller, a pair of pivatally mounted upright rods, a bearing for said contact roller mounted on each of said rolls, a single rotatable shaft for controlling the motion of said bearings for said con- 1 tact roller, a weight for rotatingsaid shaft and cables attached respectively to said rial passing between said apron and the adjacent mixing roll will cause one or the other of said upright guides to move outwardly or inwardly under the control of said weight and when one of said guides is moved the other will be free to move.

9. An attachment for mixing mills embodying a support adapted to be. secured to a mill underneath the milling rolls thereof, spaced rollers carried by the support, inclined guide rods pivoted at their lower ends to said support, a roller mounted to slide on said uide rods, an apron trained over all of said rollers, a weight operated device yieldably holding the last named roller at its upper limit of movement upon said guide rods and permitting independent rocking of either of said guide rods, and stops limiting movement of said guide rods 20 toward said milling rolls.

Signed at Providence, R. I., this 28th day of January, 1915.

HARRY A. WELTON. Witnesses A. C. KENNEDY, J. W. MURPHY. Signed at Detroit, Mich., this 26th day of January, 1915.

HOMER J. HOYT. VVitnesseS:

JOHN CARLSON, E. LA BUSCHEWSKY. 

